Mannosylated Constructs as a Platform for Cell-Specific Delivery of Bioactive Agents

Dictating the transport of drug carriers and augmenting the drug concentration at the desired anatomical site with high selectivity are worthwhile pursuits of current pharmaceutical research. Such approaches to drug targeting have been classified into passive and active strategies. As discussed in this article, active targeting promises greater selectivity because it exploits the incorporation of appropriate ligands, which are recognized by the target cells. Ligands, such as folate, peptides, transferrin, antibodies and their fragments, sugar, and sugar-mimetics, etc., with affinity to the molecules typical to or enriched in target tissues, have been investigated in this context. Mannose receptors (MRs) are abundantly expressed on a variety of cells, such as antigen-presenting cells, dendritic cells, and macrophages. Mannose receptors have lectin recognition domains that exhibit a high binding affinity for mannose. As a result, specific recognition of mannose-functionalized constructs has extensively been explored in the cell-specific targeting of drugs, vaccines, and other bioactive agents. This review outlines and discusses the key aspects of synthesis of mannosylated constructs, their mode of cellular uptake and application to targeted delivery of bioactive agents.